文档介绍：Plate Tectonics ? Sir Francis Bacon 1620: –“ It appears that South America and Africa fit together ”? Antonio Snyder published a sketch in 1655 showing . and Africa together ? Benjamin Franklin in 1782 said –“ The crust of the Earth must be a shell floating on a fluid interior. Thus, the surface of the globe would be capable of being broken and disordered by the violent movements of the fluids on which it rested. ” Theory but no evidence ? Most scientist thought it was more coincidence than fact that the landmasses appear to “ fit together. ”? Couldn ’ t fathom a process where these large landmasses moved, and they didn ’ t have any “ evidence ” that they had actually moved. Drifting Continents …? 1. first conception of the revolutionary theory of plate tectonics supported by evidence was proposed by the German geophysicist-meteorologist Alfred Wegener (1880-1930) Pangaea ? Alfred Wegener proposed the theory of continental drift in early 1900 ’s ? Wegener ’ s theorized that all the continents were once a single landmass. (Pangaea) ? All continents were once joined and began gradually moving apart, in fact they ’ re still moving. 220 million years ago Wegner ’ s theorized that all the continents were once a single landmass. ? What was the Evidence and where did it come from? ? 1- Continental shape ? 2- Fossil remains ? 3- Sea Floor Depth (Global Bathymetry- SONAR) ? 4- ic Stripes – A ic reversal is a change in the Earth's ic field such that the positions of ic north and ic south are interchanged. The Earth's field has alternated between periods of normal polarity, in which the direction of the field was the same as the present direction, and reverse polarity, in which the field was in the opposite direction. ? 5- Global Seismic (tracking Earthquakes) ? 6 - Mountain parison ? 1 Shape ? 2 -Fossil remains (Animals and Plants) Land from the South, moving North